Gaseous electric discharge metal vapor lamp device



y 13, 1937- w. YUYTERHOEVEN El AL 2,080,902

GASEOUS ELECTRIC DISCHARGE METAL VAPOR LAMP DEVICE Filed Sept. 18, 1934 W/ZdVENTORS MW van/X90422, BY 7 07(M ATTORNEY Patented --May 18, 1937 GASEOUS ELECTRIC DISCHARGE METAL VAPOR LAMP DEVICE Willem Uyterhoeven, Cornelis Verburg, and Martinus van Dam, Eindhoven, Netherlands, assignors to General Electric Company, a

- corporation of New York l Application September 18, 1934, Serial No. 744,470

In Germany September 29, 1933 I 1 Claim.

The present invention relates to gaseous electric discharge metal vapor lamp devices generally and more particularly the invention relates to circuits comprising such devices useful in illumi- 5 nating outdoor areas.

The intensity of the light emitted by metal vapor lamps is affected by changes in current and vapor. pressure. Changes in ambient temperature cause changes in the vapor pressure in the 1;) lamp and changes in the intensity of the light emitted by the lamps. When the current in the lamp is such that the heat of the discharge is sufiicient with regard to a definite ambient temperature to develop a vapor pressure such that 15 the lamp emits a maximum intensity of light a drop in ambient temperature causes a drop in vapor pressure and the lamp emits lower intensity light. An increase in ambient temperature also deleteriously affects the vapor pressure.

The object of the present invention is to provide a circuit comprising a plurality of metal vaand operation will be apparent to those skilled in the art from the following particular description.

The invention attains its object by connecting in the lamp circuit a regulating device which is controlled by the ambient temperature and which,'when the ambient temperature drops, increases the voltage supplied to the lamps, or reduces a variable impedance which is connected in 40 series with the lamps and which reduces the voltage or increases the impedance when the'ambient temperature rises. e

When the ambient temperature drops a stronger current is caused to pass through the lamps so 45 that the increase in heat radiation of the lamps,

caused by the drop in the ambient temperature, is compensated for by the increased heat developed by the discharge. In the same waythe current strength is caused .to bedecreased when v 50 the ambient temperature increases. By the above mentioned means'theadvantage is gained that the vapor pressure in the discharge lamps in the circuit is independent ofchanges in the ambient temperature.

55 In the drawing accompanying and forming part of this specification two embodiments of the invention are shown schematically in Figures 1 and 2.

The embodiment illustrated in Fig. 1 comprises a number of U-shaped, tubular, electric discharge lamps I, each of which contains a rare gas, for instance neon, at a pressure of approximately 1 to l0 mm. of mercury, and a quantity of vaporizable metal, such as sodium, the vapor of which participates in the light emission of the discharge lamps when excited to luminescence by the passage of an electric discharge therethrough. A thermionic electrode is sealed into each end of said lamps I. Further structural details of the discharge lamps are omitted as such details are well known and need not be described here since they are not essential for an understanding of the present invention.

'the primary coil 8 is mounted and said coil 8 is nectedto said lever l3 intermediate the ends of The discharge lamps are connected to the secondary coils 2 of the transformers 3; the primary coils 4 of which are connected in series with each other and are connected with the secondary transformer coil 6 over an external impedance 5.

This transformer comprises a core 'I on'which connected to the terminals-of an alternating current source. This primary coil 8 has a fixed position on said core I while the secondary coil 6 is adjustablevertically and is hung on the balance 9 which is provided with a counter-weight III. The are shaped member H of this balance 9 is adjusted in such manner that the lever arm of the counter-weight ID has different lengths for various positions of the balance 9. This shape of the member II is selected in order that, for all positions of the balance 9, the counter-weight 1 i0 is in equilibrium with the inherent weight of the coil 6 and the attractive power between coils 6 and 8.

The movements of the balance 9, and therewith those of the coil 6, are controlled solely by the regulating device H which is responsive to changes in ambient temperature and consists of t a metal rod with a relatively high heat-expan sion coeilicient. The rod I2 -is pivoted in the fixed bracket 28 and is connected with the balance 9 by the lever l3 and the connecting arm 30. Said lever I3 is pivoted 'at' one end thereof in the fixed bracket 29 and said rod i2 is pivotally consaid lever l2. The arm 30 is pivotally connected td lever l3 and balance 9 as shown.

the coils 6 and 8 is reduced. The primary leaky field of the transformer thus becomes smaller and a higher potential is induced in the secondary coil 6. This higher potential causes an increase of the current flow through the discharge lamps which increases the heat developed by the discharge in these lamps. The circuit is regulated in such manner that this increased heat or the discharge equalizes the increased heat radiation caused by the drop in ambient temperature so that the metal vapor pressure in the 'discharge lamps always has the same value.

Instead of 'a regulating device comprising a solid metal element which exerts the necessary force, a liquid column is used, when desired. The change in the volume of the liquid when an ambient temperature change occurs is utilized to move the balance 9. The use of a liquid has the advantage that substances having an appreciably greater expansion coefllcient than the solid metals-can be used. I

The illuminating system illustrated in Fig. 2 is connected to the terminals l4 oi. a direct current source and comprises a number of linear discharge lamps l5 which have thermionic electrodes and a gaseous filling comprising a metal vapor. An external resistance i6 is connected inseries with these discharge lamps l5. Various taps I! on this resistance are connected with contacts i8 which are connected in pairs by the contacts I 8 whereby the parts 20, 2| and 22 oi! the resistance i6 are short circuited. The contacts i9 are lifted by the magnet coils 23 whereby the short circuit of the above mentioned parts of the resistance is broken. The coils 23 are connected at one end to one terminal of a batfew 24 and at the other end to contact members 25 mounted in spaced positions along the glass tube 26 which contains an amount of mercury This mercury is connected to the other terminal oi the battery 24.

When the ambient temperature increases the mercury rises in the tube 2!. In doing this it touches the first contact member 25 and the left hand coil 23 is energized and lifts the contact I! to open the short circuit oi the resistance section 20 so that the resistance, which isconnected 'in series with the discharge lamps, is increased.

The current through the lamps and the heat developed by the discharge in the lamps is reduced so that the vapor pressure-is unchanged. It the ambient temperature increases still farther the coils 23 are energized in sequence and the short circuit of the resistance sections 2| and 22 is opened whereby the strength of the current through the discharge lamps is still farther reduced and the vapor pressure remains unchanged. On alternating current operation, one can also use a choke coil as external impedance and change the size of this choke coil by the regulating device. I

While we have shown and described and have pointed out in the annexed claim certain novel features oi! the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its use and operation may be made by those skilled in the art without departing from -the broad spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:-

An illuminating system comprising in combi- 

